KRAMERS-TYPE PICTURE FOR CRYSTAL NUCLEATION

We introduce a new scheme to analyze the kinetics of homogeneous nucle ation in terms of a global order parameter. Our approach is based on t he application of the internal degrees of freedom formalism to derive a kinetic equation of the Kramers type formulated for a global reactio n coordinate. We provide explicit expressions for the quantities and c oefficients involved in the process, suitable for simulation. In addit ion, our picture recovers in the quasistationary case the transition r ate obtained from the method of reactive, flux. The equation we presen t may provide a link between theoretical approaches to homogeneous nuc leation (generally formulated in terms of a kinetic equation of the Fo kker-Planck type) and simulations (which mostly employ linear response theory). In this context, our scheme provides a theoretical framework to interpret and extend the results obtained in recent simulations. ( C) 1998 American Institute of Physics. [S0021-9606(98)50538-7].